Polyvalent metal mono and dicarboxylic acid soap thickened lubricating oil



United States Patent" Office 2,859,179 Patented Nov. 4, 1958 POLYVALENT NIETAL MONO AND DICARBOX- YLIC ACID SOAP THICIGENED LUBRICATING 01L John H. Lux, Baltimore, Md., and Konrad Parker, Chicage, 11]., assignors to Witco Chemical Company, a corporation of Illinois No Drawing. Application January 4, 1955 Serial No. 479,844

2 Claims. (Cl. 252-35) This invention relates to greases prepared with soaps comprising polycarboxylic acids.

In copending application Serial No. 133,957, filed December 19, 1949, which issued as U. S. Patent No. 2,699,428, new soaps-are described which are prepared by co-reacting a hydroxide with'fatty acidmaterial which includes a small proportion of polycarboxylic acid or acids. The co-forming of such soaps produces materials which are soluble in lubricating oils whereas normally the reaction product of a carboxyli acid with a metal to form a soap is not soluble.

This application isa continuation-impart of our copending application Serial No. 133,956, filed December 19, 1949, now abandoned. i

The greases produced from soaps of this new form are remarkably better than greases heretofore known.

Present greases are deficient in a number of respects. Of these the most important is thelack of ability of the greases to withstand working. While an oil does not wear out under use,- greases hitherto known "did. Standard working tests are known for greases, and a grease which stood up for 5,000 strokes'of thetesting machine Without breakdown was considered a good grease. By means of the present invention greases may be produced which show no substantiakbreakdownpr deterioration between 5,000 strokes and 100,000 strokes.

Another defect of pres'entgreases is that they do' not set well at high temperatures; Thus, on a warm day'it may be impossible 'to' produce a satisfactory grease, and even after production of a grease'at'a lowtemperature, it tends to-bleed or break down at a'higher'temperature. The greases of the present'invention',produced'with the soaps described, will wet at temperatures markedly above those heretoforepossible, are-stable at higher temperatures, and will set more quickly.

Another defect'of former greases hasbeen the inability to procure a very stiff grease without also'makingfjit grainy. The new improved greases' may be madestiflfer than before without spoiling" thegrease structureand generally with less soap than-was heretofore required.

The greases of the present invention embody'prim'arily aluminum soaps, but soaps ofother metals are also -useful, as for example sodium, lithium, calcium, barium, magnesium, zinc and lead.

The fatty acids which may be employed are normally between 8 and 22 carbon atom molecules. Normally these are referred to as stearic acids in commerce, but actually they may include much or all of other acids such as palmitic, myristic, lZ-hydroxystearic, 9,10-dihydroxystearic, oleic, lauric, behenic and ricinoleic. The proportion of these acids does affect the soap and the ultimate grease. Therefore, grease formations with any particular soap is to some extent a matter of test and adjustment. One of the advantages of these soaps, however, is that they Work substantially equally well with oils from various origins, whereas previously greases had to be carefully compounded with oils from selected sources.

'cal structure of the soaps is not specifically known.

The soap employed need not be completely reacted. For example, aluminum may form mono, di or tri salts, and normally the di salt is that employed. The other salts may likewise be used.

A preferred carboxylic acid is a dibasic acid, and the preferred dibasic is. sebacic. The dimer of linoleic acid, known commercially as Emery M461-R is likewise particularly good. Adipic, pimelic and suberic acid have likewise produced very satisfactory greases.

The amount of polycarboxylic acid used may vary from 0.5% to 25% of the total acid by weight. Normally the ratio will be from 5'20% polycarboxylic acid and from -95 by weight of monocarboxylic acid.

As set forth in said copending application, the chemi- It is assumed, however, that cross linkages are produced within the molecules so that highly linked structures of three dimensional characteristics are produced which are soluble in oils, the solubility presumably depending upon the preponderance of two dimensional chains in the molecules. Mere mixtures of separately formed polycarboxylic acid soaps and-monocarboxylic acid. soaps do not produce solubility in the polycarboxylic acid portions thereof.

The following examples illustrate the preparation of suitable greases:

Example 1 A mixture of 84 parts of hydrated lime with 1,000 parts of 300 S. U. V. 100 oil was added to 640 parts of a 40:40:20 of stearic, oleic and sebacic acids. This mixture was then heated to 250" F. until saponification was complete. The mixture was then cut back to a 10.0% soap content with more oil. The'grease was then run through a homogenizer. The worked penetration of the grease was 260-270.

A similar grease made without the 'dicarboxylic acid gave a penetration of 370 at thesame soap content.

Examplei parts of hydrogenatedherringacidsand 5' parts of sebacic acid were-saponified with 22 parts'o'f caustic soda in aqueous solution; Aluminum sulphate was added in excess until thesolution. hadua pH of- 5. The solid precipitate was filtered, washed, driedand ground. (Aluminum Soap A.). 6% of this-.producowasv dissolved in a -Mid-Continent oil (3008.48. .at F1) at- 300 FI- to. form a. stiff gel. Forncomparativ'eapurposes a similar sample was made using 100 gnamshydrogenated herring acid and no sebacic acid. (Aluminum Soap B.)

Comparative penetration results of greases (at 77 F.) containing. 6% of S0aps--A- and- B areshown in the following-table: ,7

Example 3 One part of lithium hydroxide and 6 parts of water were stirred together at 180 F. and then caused to react with 6.5 parts of 12-hydroxy stearate and 05 part of sebacic acid in 15 parts of a 100' S. S. U. at 100 F. oil. At the end of the reaction the temperature was raised to 300 F. to eliminate the water from the mixture. Seventeen parts of oil were then added and the temperature was raised to 380 F. for 2 hours. The temperature was decreased to 200 F. by adding enough oil to give a lithium soap content of 12% and the entire composition was pumped through a 60 mesh screen. The worked penetration of the resultant mixture was 305. A similar run without the sebacic acid gave a grease that was too thin to take penetrations on.

Example 4 Unworked Worked 5,000

Example 5 Unworked 5,000

60 Strokes Strokes Example 6 A soap made and treated as Example 2 except that raw materials were 90 grams of hydrogenated herring acid and grams of Emerys 461R dimer acid.(Aluminum Soap E). A grease made as in Example 2 containing 6% of this soap gave penetrations as follows:

Unworked 60 5,000

Strokes Strokes Example 7 In order to check the efiect of higher concentration of dicarboxylic acids a soap was made up using 85 grams of hydrogenated herring acid and 15 grams of Emerys 461R dimer acid. A grease made as in Example 2 containing 6% of this soap gave the following penetrations:

Unworked 60 5,000

Strokes Strokes Aluminum stearate greases prepared by dissolving six parts of aluminum stearate with 94 parts of oil using the material described in Example 6 gave excellent results with all the different types of oils tried. Results with the various oilsare shown in the following table.

In every instance it will be noted that the penetration of yield of the grease was superior for the soap prepared in Example 6 and in addition the change in penetration on working (delta value) was smaller in every instance than for soaps not containing the dicarboxylic acid.

As further evidence of the efiiciency of the stearate prepared in Example 6, greases were made up using a a lower percentage of stearate. The following tables show that products with contents as low as 3 /2 of aluminum stearate make greases of exceptionally good worked stabilityr Penetrations 60 5,000 Stroke Stroke Mideontinent Stock, 300 SSU 100 F.:

4.0% Aluminum Soap E 335 365 4.5% Aluminum Soap E 310 345 5.0% Aluminum Soap E" 290 320 5.5% Aluminum Soap E 270 300 6.0% Aluminum Soap EL- 250 280 Gulf GoastalStock, SSU 210 F.

3.5% Aluminum Soap E" 335 a 365 4.5% Aluminum Soap E 295 325 5.0% Aluminum Soap E 270 300 6.0% Aluminum Soap 31".. 230 p 260 In order to determine the effect of oxidation resistance upon the finished grease, greases made up from the stearate described in Example 2 were subjected to test in a Norma Hoffman bomb. Oxygen pressure dropafter hours at 210 F. was three pounds or less for all greases made with Pennsylvania base structure. This showed that the stearates have no efiect upon the oxidation resistance of the finished grease.

The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom as modifications will be obvious to thosev skilled in the art.

We claim:

1. A grease comprising a lubricating oil and a grease thickening amount of a polyvalent metal soap, said soap comprising soap molecules co-formed by reaction of polyvalent metal ions with mixed mono and polycarbox-' ylic acids, said polycarboxylic acid in the soap is sebacic acid, the proportion of sebacic acid being fromabout 0.5% to 25% of the total carboxylic acid by weight, and the monocarboxylic acid being of the class consisting of the fatty acids containing from 8 to 22 carbon atoms.

2. A grease as set forth in claim 1 in which the soap is an aluminum soap and the metal ions are aluminum UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,859,179 November A, 1958 John Ho Lux et al.,

It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 6, after "dibasic" insert acid column 4, line '7,

after "using" strike out "a",

Signed and sealed this 24th day of March 1959.,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents 

1. A GREASE COMPRISING A LUBRICATING OIL AND A GREASE THICKENING AMOUNT OF A POLYVALENT METAL SOAP, SAID SOAP COMPRISING SOAP MOLECULES CO-FORMED BY REACTION OF POLYVALENT METAL IONS WITH MIXED MONO AND POLYCARBOXYLIC ACIDS, SAID POLYCARBOXYLIC ACID IN THE SOAP IS SEBACIC ACID, THE PROPORTION OF SEBACIC ACID BEING FROM ABOUT 0.5% TO 25% OF THE TOTAL CARBOXYLIC ACID BY WEIGHT AND THE MONOCARBOXYLIC ACID BEING OF THE CLASS CONSISTING OF THE FATTY ACID CONTAINING FROM 8 TO 22 CARBON ATOMS. 